Childhood sexual abuse is major public health problem that affects 16 percent of women in this country before their 18th birthday. Animal studies showed that high levels of cortisol seen in stress are associated with damage to the hippocampus, a brain area involved in learning and memory, with associated memory deficits. The investigator has been a pioneer in showing a reduction in hippocampal volume based on magnetic resonance imaging (MRI) and memory deficits in patients with PTSD related to combat and childhood abuse. The current revised R01 application proposes to use positron emission tomography (PET) to measure hippocampal function during the "real time" performance of declarative memory tasks, in addition to MRI-based measurements of hippocampal volume, in childhood abuse-related PTSD. Women with PTSD related to childhood sexual abuse will be compared to two control groups: 1) women with childhood sexual abuse without a history of PTSD (abused non-PTSD controls), and, 2) women without childhood sexual abuse and without a history of PTSD (non-abused, non-PTSD controls). Research in this area has enormous potential to help women with childhood sexual abuse-related PTSD. For instance, animal studies showed that specific medications can block cortisol-mediated hippocampal injury seen during stress. The specific aims of this revised application are therefore to: 1) compare hippocampal activation during verbal memory tasks (measured with PET) between abuse-related PTSD and controls. We hypothesize a failure of hippocampal activation in abuse-related PTSD; 2) compare hippocampal volume (measured with MRI) between abuse-related PTSD and controls. We hypothesize a reduction of hippocampal volume in abuse- related PTSD which is specific to hippocampus (specificity will be measured with grey-white segmentation); 3) assess the relationship between hippocampal activation measured with PET and hippocampal volume measured with MRI. We hypothesize a relationship between a failure in hippocampal activation and hippocampal volume reduction in patients with PTSD.